A super-quick guide to manhole covers and frames
A manhole cover or maintenance hole cover is a removable plate that forms the lid over the opening of a manhole. A manhole is a large opening which is designed to help a person to pass through it and is used as an access point for an underground vault or pipe. The main purpose of it is to prevent anyone or anything from falling in and to keep any unauthorized personnel out. Dutco Tennant LLC supplies a wide range of manhole cover and frame in the Middle East.
Types of manhole covers-
Ductile Iron –
Most commonly, these covers and frames are made up of Ductile Iron. But why so? ‘Spheroid Graphite’ or ‘Ductile Iron’ is a unique form of Iron which before the metal casting process receives crucial mineral additives for producing an exceptionally strong resistance and durable metal. The rise of excellent additional strength and shock load resistance is given by the molecular structure of ‘Ductile Iron’ within structure carbon steel, without steel inheriting corrosion. In modern-day roads, cover and gratings are important for carrying out the increasingly heavy and fast-moving traffic and also to keep the roads in service, places free from accidents and theft. Adding to that manhole cover and frame also important in terms of achieving speed and ease of access for maintenance of services. The conventional ‘Grey Iron Manhole Covers, Gratings and Frames are rapidly being replaced by the ‘Ductile Iron’ Manhole Covers, Gratings, and Frames on account of uniqueness in its Strength to Weight ratio, Design, Weight and the Cost-benefit.
Advantages of using Ductile Iron Manhole Covers and Frames –
- Offers high strength which results in more life and durability
- Is available with Elegant Checkers Design, offers Good Anti-skid Grip and Nice Appearance.
- The chances of theft are also less because of its hinge type design.
- It is suitable for Heavy Traffic Loading and at High speed.
- It does not break suddenly, so the chances of accidents are almost reduced.
- Ductile Iron’ Minimises the Risk of Failure during normal uses and offers Resistance to Impact
- The high strength to weight ratio of Ductile Iron allows the manufacturers to relatively manufacture Light Weight Castings
- Very Easy to Handle
- Costs Less as compare to Cast Iron
- Light Weight, More Strength
- More Load Bearing Capacity
These type of covers have recessed areas which are suitable for laying block paving or a layer of screed, They are great for decorative finishes in driveways. The loading classes for recessed covers are rated to FACTA loading specifications.
Solid Top –
These lighter galvanized steel manholes often fitting flush at ground level and have inset grab handles. They are mainly used for lighter uses.
Weight classes of Manhole Covers:
- A15 (Capable of withstanding a 1.5-ton test load):- Pedestrians and Pedal Cyclist.
- B125 (Capable of withstanding a 12.5-ton test load):- Car parks and pedestrian areas manhole covers where only occasional vehicular access is likely.
- C250 (Capable of withstanding a 25-ton test load):- Car parks, forecourts, areas with slow-moving traffic.
- D400 (Capable of withstanding a 40-ton test load):- Car and Lorries have access, including carriageways, hard shoulders and pedestrian areas.
- E600 (Capable of withstanding a 60-ton test load):- Loading areas, Docks, etc.
- F900 (Capable of withstanding a 90-ton test load):- Aircraft pavements.